Since 1990, the Center for Mapping at Ohio State University has been developing mobile mapping systems to automate and accelerate the collection of digital map data. These systems integrate the global positioning system (GPS) with inertial navigation units and imaging sensors to produce digital geographic data. They are modular and can be installed on various platforms, such as vans, trains and aeroplanes. New developments with the imaging system and the fully integrated data‐processing environment are discussed in this article. The stereovision system enables the user to obtain three dimensional co‐ordinates of any object in the field of view of the camera. Digital and video images, together with GPS positions, are stored in an object‐oriented database, which merges data collected by airborne and terrestrial mapping platforms. Exploiting the enormous amount of information contained in the digital stereoscopic imagery is a challenging topic of current and future research.
A mobile mapping system which integrates the global positioning system (GPS) and stereo cameras was developed by the Center for Mapping of the Ohio State University. This system was calibrated using the bundle adjustment with the relative orientation constraints. To extract the useful data from those images, a three-step image matching method based on the epipolar geometry was developed: first, the approximated position is estimated from the system geometry; second, the cross correlation method with the significant maximal coefficient was used. A variable size of template is employed to find the significant maximal correlation coefficient. Third, least squares matching was used to have the sub pixel accuracy. Using this matching method, the point, profile and surface can be measured by selecting points in a single image of a stereo pair. Finally, this technique is extended to extract three dimensional edges by line following. All data captured by the mobile mapping system are available in a global coordinate system.
Aerial triangulation controlled by GPS observations in the aircraft has been established as a precise method of photogrammetric point determination without the need of ground control. If the GPS observations are available for blocks of aerial photos, the aerial triangulation can be carried out without any ground control points. Unfortunately, this method cannot be applied for single flight lines, since the GPS observations do not recover the roll angle of the aircraft. Therefore, ground control is mandatory for GPS controlled strip triangulation. This paper investigates GPS controlled strip triangulation using known, linear features on the ground that are approximately parallel to the flight line. This described technique models the linear feature in the images by low order polynomials and forces the known line on the ground onto this function. Thus, the roll angle can be determined. We investigate the effects of different GPS measurement accuracies both in the air and on the ground on the results. Experiments using simulated and real data are presented. We also show that this new technique is useful for mapping railroads.
At The Center for Mapping of The Ohio State University, a mobile mapping system was developed. By integrating the global positioning system (GPS) with a stereo vision system, the global coordinates of any point in the field of view of the cameras can be obtained. The calibration of cameras was done by using the bundle adjustment in a test field of retro reflective targets. The image coordinates are measured automatically by means of the center of gravity, the identification of points is also performed automatically using the space resection. As the stereo cameras are mounted on a stationary platform, relative orientation constraints are applied in the calibration. As a result, the number of required observations is reduced and a stable calibration of the stereo vision system is achieved. The modifications to the standard bundle solution are presented, as well as the positioning accuracy of the calibrated system.
Different methods can be applied to generate digital orthophotos. Three commonly used approaches are analyzed and compared in this paper. They can be applied to rectify both digitized aerial photographs and satellite scenes. These methods are polynomial, projective, and differential rectifications. The first two are defined by analytical transformations between image and orthophoto without considering the geometry and orientation of the camera. They are approximate solutions. The last one models the physical reality of the imaging process by means of the collinearity equations and corrects for relief displacements. All three methods were implemented on a workstation and were tested with digitized aerial photographs and video images. By overlaying GIS data over the digital orthophoto, the quality of the rectification is checked. To determine the planimetric accuracy of the results, the coordinates of targets were measured in a digital orthophoto and compared to known map coordinates.
This CD-ROM accompanies NCHRP Report 506, Quality and Accuracy of Positional Data in Transportation. It contains a prototype error model that can be used to understand the effects of using and combining typical data sources. The outputs of the model list the confidence values at various probabilities associated with specific data sources for a wide range of transportation applications. The error model is implemented as a software program called GISError. It was developed in Visual Basic with a graphical user interface. A user guide for GISError is included in NCHRP Report 506 as Appendix A.
This report presents guidance for practitioners on the use of positional, or spatial, data in Geographic Information Systems (GIS) for transportation applications. As GIS applications become more common in transportation system management and decision making, concerns have grown about the accuracy of the data used to populate them. Transportation spatial data usually describes the location of features on the highway system using a one-dimensional linear referencing system. The level of accuracy varies by data source and is affected by the precision of the measurement system used to collect it. Agencies need a way to understand the errors that may result when using these data in GIS applications and how these errors may be compounded when combining data from various sources. This project reviewed the linear referencing systems used by state departments of transportation, examined the limitations of typical data sources used in these systems, and developed a model to evaluate the effects of varying data accuracy and provide an assessment of the level of confidence in the system outputs. This report will provide valuable information to transportation practitioners who need to understand and account for the level of precision in GIS-based transportation decision tools.
Bei Aufhebung von Pkw-Kaufvertragen mit schuldrechtlicher ex-tunc-Wirkung ist (neben der Herausgabe des erhaltenen Kaufpreises bzw. des Kaufgegenstandes in natura) von den Parteien des Kaufvertrages Benutzungsentgelt zu leisten.
Der OGH hatte bis dato kein alle beurteilungsrelevanten Aspekte berucksichtigendes Berechnungsmodell zu erarbeiten. Seinen Erwagungen in den wenigen bis dato ergangenen Entscheidungen sind jedoch Grundsatze zu entnehmen, nach welchen die Bemessung vorzunehmen ist. Diese scheinen manchen Stimmen in der Lit und auch Teilen der Jud als zu verkauferfreundlich. Teils wird zur Bemessung das kauferfreundliche Berechnungsmodell des BGH herangezogen, statt die Erwagungen des OGH umzusetzen.
Die Thesis analysiert erstmals die in Jud und Lit vertretenen Berechnungsansatze des Benutzungsentgelts auch aus wirtschaftswissenschaftlicher Sicht. Der deutsche Ansatz wird, die gesamte deutsche Jud in eine Formel integrierend, weiterentwickelt. Nach Judikaturanalyse der Rsp des OGH wird – als Pendant zur deutschen Formel, jedoch die osterreichische Rsp zugrunde legend – ein tragfahiges Berechnungsmodell erarbeitet. Dieses ermoglicht auch dem nicht betriebswirtschaftlich gebildeten Rechtsanwender nach Abarbeitung eines kompakten Fragenprogrammes eine samtlichen Erwagungen der osterreichischen Rsp Rechnung tragende und gleichzeitig wirtschaftswissenschaftlich fundierte Selbstberechnung des Nutzens unter Heranziehung von kostenfrei zuganglichen Datenbanken.
Moving targets are tracked in space by two CCD-cameras, which are oriented using control points. Image coordinates are determined automatically by thresholding and correlation methods. To solve the correspondence problem, nearest neighbor and direction criteria are applied in the image plane, and epipolar contstraints in the stereo setup. Accuracy can be tested by a moving target produced by a plotter. These algorithms run in the window environment of a Sun-workstation equipped with image acquisition boards.
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